Orange and T-Mobile customers wishing to use the new ultra-fast 4G mobile phone service will have to fork out as much as £56 a month for the privilege.

4G, to be launched in the UK on 30 October by Orange and T-Mobile's parent company EE, delivers speeds up to five times faster than 3G. Consumers will be able to download and stream music and videos easily while on the go, with a standard definition movie taking just 10-15 minutes to download.

EE has now published its price plans for the 4G service, revealing that two-year contracts range from £36 to £56 a month depending on how much data you use. Unlimited calls, texts and a 500MB data allowance will cost £36, rising to £41 for 1GB, £46 for 3GB, £51 for 5GB and £56 for 8GB.

The cost is around £5 a month more than Orange and T-Mobile's current 3G tariffs.

EE also unveiled Sim-only pricing for those who already have a 4G phone, with plans with 500MB a month of data costing £21, 1GB costing £26, 3GB for £31, and 5GB costing £36.

Olaf Swantee, chief executive of EE, said the pricing was competitive. "We will deliver consumers and businesses across the country next-generation services and a superior level of support. Our new plans have been developed to offer our customers everything they have been asking for – superfast performance, choice and value."

Consumer groups agreed that the pricing was attractive but said the 500MB cap would be quickly used up by anyone streaming movies and music.

Dominic Baliszewski, telecoms expert at BroadbandChoices, said: "The starting download limit is 500MB with the cheapest package – enough to get you through light emailing and surfing but this will never be a replacement for the much more generous download limits that come with landline broadband packages that allow you to stream and download without worrying about data usage – so don't ditch the line rental just yet."

He added: "Given the much faster speeds 4G can deliver, early adopters of this service will likely want to make the most of its capabilities and may be forced to opt for the pricier packages such as the 8GB data package at £56 per month."

Regulator Ofcom will be holding an auction in January 2013 at which mobile phone operators can bid for a 4G licence, but it surprised the industry earlier this year by giving EE the go-ahead to exclusively launch 4G in the UK from September 2012.

4G-ready phones (including the iPhone 5, the HTC One XL and the Samsung Galaxy S III) are already on the market, and EE said its customers in the first six months of their contracts could upgrade their iPhone 4S, Samsung GSIII, HTC OneX handsets to a 4G handset for a one off fee of £99.

But Baliszewski warned that consumers who rush into a deal could pay more in the long run. "EE has an excellent track record for service but more providers competing for your custom means cheaper prices and better terms for you, so it could be worth waiting a little longer before signing up," he said